MUI will automatically format the text according to the width of the floattext object. If a word won't fit into the current line, it will be wrapped.
If you plan to use tabs not only at the beginning of a line you should consider using the configured fixed width font.
MUI copies the complete string into a private buffer, you won't need to keep your text in memory. If memory is low, nothing will be displayed. Thats why you always have to be prepared for handling a NULL pointer when getting back MUIA_Floattext_Text.
Setting MUIA_Floattext_Text to NULL means to clear the current text.
Please note that justification and word wrap with proportional fonts is a complicated operation and may take a considerable amount of time, especially with long texts on slow machines.